Evolutions of the UMTS (“Universal Mobile Terrestrial System”) mobile communication network standardized by the 3GPP organization are under discussion. These evolutions constitute the basis of a future fourth generation and are also called LTE (“Long Term Evolution”). They envisage in particular an evolution of the core network EPC (“Evolved Packet Core”) in which the exchanges are performed solely in packet mode. During its attachment to the mobile network, the user equipment UE establishes a session with a packet data network and obtains an address in this network. Thus, the user equipment possesses permanent connectivity as long as it is attached to the mobile network. The user equipment UE is identified by an IPv4 address and/or by an IPv6 prefix. The packet data network is for its part identified by an identifier of the data network APN (“Access Point Name”). This session is also called “PDN connection”, PDN for “Packet Data Network”. Such a session comprises at least one medium, called “bearer”, by default and can comprise one or more dedicated media.
This session is established between the user equipment UE and the data network by way of an access gateway P-GW. This access gateway P-GW is the facility of the mobile communication network in charge of the interface with the packet data network. A gateway P-GW can thus make it possible to access services offered on the Internet communication network or else services offered by an operator.
An operator of the communication network may desire to have a certain flexibility in the choice of the access gateway as a function of a service requested by the user equipment. It is not possible in the current version of the standards to modify the access gateway P-GW, which has made it possible to establish a session.